The present invention relates to a braking device for furniture doors having a horizontal pivotal mounting, such as flap doors and the like.
On construction of elements for furniture it is often necessary to open a door using a single- or multi-pivot kinematic mechanism disposed in such a manner that the instantaneous-rotation axis will be horizontal. Classical examples are flap doors and some hanging furniture (wall cabinets for kitchens, for example) where opening of the door upwardly instead of laterally as in normal applications can be convenient.
In the case of an opening along a horizontal rotation axis however, there is a problem because the centre of gravity moves on a vertical plane so that the door tends to drop towards its position of maximum opening (in the case of flap doors) or its closing position (in the case of furniture in which the door rotates upwardly). Therefore, for these applications the door movement is required to be balanced so that said movement is at all events smooth and uniform also in the direction of action of the door weight or even to enable the door itself to keep a steady position irrespective of its location, exactly as it happens for doors with a vertical rotation axis. For this reason different cam systems are used and known in the art which utilise springs or gas cylinders to balance the door weight.
If the door weight is not too heavy, the balancing mechanism can be advantageously replaced by a xe2x80x9cpassivexe2x80x9d friction joint which is cheaper and limits itself to brake the weight-force action. In this case a problem exists because it is necessary to make a cheap and stout mechanism of the one-way type, i.e. in which the movement is braked in the direction of action of the door weight, and which is instead free in the opposite direction so that a useless effort is not required. Systems using ratchet gears and toothed surfaces have been suggested in the known art which are however rather expensive, sometimes noisy, and often provided with excessive mechanical slacks.
It is a general aim of the present invention to supply a braking device which, applied to a pivot of the kinematic mechanism of a hinge or the rotation axis of a balancing rod, produces a rotation-resistant adjustable torque acting in one rotation direction alone, with a rotation in the opposite direction practically clear of frictions. All that at reduced costs, with a stout and reliable structure and minimum operating slacks.
In view of the above aim, in accordance with the invention, a device for a braked movement in furniture doors in particular with a horizontal rotation axis has been conceived which comprises two attachment pieces that are movable in opposite directions around a common rotation axis in a free manner in one rotation direction and against a resisting force obtained by a friction joint in the other rotation direction, the friction joint being connected to one of the two attachment pieces through a one-way wedging device, characterised in that the wedging device comprises a first surface integral with the attachment piece and a second surface integral with the joint, the two surfaces facing each other to delimit a space therebetween in which a selective-wedging element is disposed, the extension of the facing surfaces and/or the shape of the wedging element between them being of such a nature that the wedging element tends to fixedly fit between said facing surfaces so that they are caused to rotate integrally with each other when rotation of the two attachment pieces takes place in the direction that must involve a braked movement.